feat(0.30.0): colonnes personnalisables par espace + mapping étiquette ↔ colonne

- Table board_columns par espace (clé immuable, nom/couleur/
  ordre libres, étiquette mappée + alias, drapeau Focus) ;
  définitions semées paresseusement depuis les valeurs
  historiques — sans personnalisation, comportement identique.
- Service app/board_columns.py : résolution, mapping
  étiquette→colonne (alias compris, ex. kanban_a_faire de
  Flowdeck), colonnes Focus/Wallboard.
- Board, API, adoption, miroirs d'étiquettes, déplacements,
  capture, santé, focus, wall, dashboard branchés sur les
  colonnes de l'espace ; validations dynamiques dans models
  (move_issue, set_column_order) et rules.
- Administration → Colonnes : ajouter (avant Terminé),
  renommer, réordonner, mapper, supprimer avec migration des
  cartes vers une colonne choisie, réinitialiser ; bouton
  🧱 Colonnes sur le board ; journal d'audit.
- Backlog et Terminé : colonnes système non supprimables.
- 254 tests verts (7 nouveaux, palier 20) ; smoke réel contre
  le vrai Gitea : création, affichage au board, suppression.

app/models.py

@@ -154,6 +154,21 @@ def init_db() -> None:
                 created_at TEXT NOT NULL DEFAULT (datetime('now'))
             );
 
+            -- ── Colonnes personnalisables par espace (0.30.0) ──
+            CREATE TABLE IF NOT EXISTS board_columns (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                workspace_id INTEGER NOT NULL,
+                key TEXT NOT NULL,
+                name TEXT NOT NULL,
+                color TEXT NOT NULL DEFAULT '#6b7280',
+                position INTEGER NOT NULL DEFAULT 0,
+                label TEXT NOT NULL DEFAULT '',
+                aliases TEXT NOT NULL DEFAULT '',
+                kind TEXT NOT NULL DEFAULT 'flow',
+                in_focus INTEGER NOT NULL DEFAULT 0,
+                UNIQUE(workspace_id, key)
+            );
+
             CREATE TABLE IF NOT EXISTS workspace_connections (
                 workspace_id INTEGER NOT NULL,
                 connection_id INTEGER NOT NULL,
@@ -219,7 +234,10 @@ def _migrate(conn: sqlite3.Connection) -> None:
     # get_board_state() with a KeyError. Drop them once, here.
     placeholders = ",".join("?" for _ in KANBAN_COLUMNS)
     conn.execute(
-        f"DELETE FROM board_state WHERE column_name NOT IN ({placeholders})",
+        f"DELETE FROM board_state WHERE column_name NOT IN ({placeholders}) "
+        "AND NOT EXISTS (SELECT 1 FROM board_columns bc "
+        "WHERE bc.workspace_id = board_state.workspace_id "
+        "AND bc.key = board_state.column_name)",
         KANBAN_COLUMNS,
     )
 
@@ -340,7 +358,9 @@ def get_board_state(
             (workspace_id, connection_id, repo_full_name),
         ).fetchall()
 
-    columns: dict[str, list[dict]] = {col: [] for col in KANBAN_COLUMNS}
+    columns: dict[str, list[dict]] = {
+        col: [] for col in column_keys(workspace_id)
+    }
     for row in rows:
         column = row["column_name"]
         if column not in columns:
@@ -364,7 +384,7 @@ def move_issue(
     connection_id: int = 1,
 ) -> None:
     """Move an issue to a different column (appended at the end)."""
-    if to_column not in KANBAN_COLUMNS:
+    if to_column not in column_keys(workspace_id):
         raise ValueError(f"Invalid column: {to_column}")
     with get_db() as conn:
         row = conn.execute(
@@ -400,7 +420,7 @@ def set_column_order(
     its index in the list. Used after a drag & drop so manual ordering
     survives reloads.
     """
-    if column_name not in KANBAN_COLUMNS:
+    if column_name not in column_keys(workspace_id):
         raise ValueError(f"Invalid column: {column_name}")
     with get_db() as conn:
         for index, issue_number in enumerate(ordered_issue_numbers):
@@ -793,11 +813,10 @@ def get_stats() -> dict:
 
     projects: dict[str, dict[str, int]] = {}
     for row in rows:
-        if row["column_name"] not in KANBAN_COLUMNS:
-            continue
         name = row["repo_full_name"]
         if name not in projects:
             projects[name] = {col: 0 for col in KANBAN_COLUMNS}
+        # Les colonnes personnalisées (0.30.0) s'ajoutent au vol.
         projects[name][row["column_name"]] = row["cnt"]
     return projects
 
@@ -1253,3 +1272,114 @@ def list_admin_audit(limit: int = 100) -> list[dict]:
             (limit,),
         ).fetchall()
     return [dict(r) for r in rows]
+
+
+# ── Colonnes de board personnalisées (0.30.0) ─────────────
+# Définitions PAR ESPACE : clé immuable, nom/couleur libres,
+# étiquette forge mappée (+ alias reconnus à l'adoption).
+# Sans lignes pour un espace, column_keys retombe sur les
+# défauts historiques — comportement 0.24 strictement conservé.
+
+def list_board_columns(workspace_id: int) -> list[dict]:
+    with get_db() as conn:
+        rows = conn.execute(
+            "SELECT * FROM board_columns WHERE workspace_id = ? "
+            "ORDER BY position, id",
+            (workspace_id,),
+        ).fetchall()
+    return [dict(r) for r in rows]
+
+
+def column_keys(workspace_id: int = 1) -> list[str]:
+    """Ordered column keys of a workspace (defaults if unset)."""
+    cols = list_board_columns(workspace_id)
+    if not cols:
+        return list(KANBAN_COLUMNS)
+    return [c["key"] for c in cols]
+
+
+def upsert_board_column(workspace_id: int, column: dict) -> None:
+    with get_db() as conn:
+        conn.execute(
+            """INSERT INTO board_columns
+                   (workspace_id, key, name, color, position, label,
+                    aliases, kind, in_focus)
+               VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
+               ON CONFLICT(workspace_id, key) DO UPDATE SET
+                   name = excluded.name, color = excluded.color,
+                   position = excluded.position, label = excluded.label,
+                   aliases = excluded.aliases, kind = excluded.kind,
+                   in_focus = excluded.in_focus""",
+            (
+                workspace_id, column["key"], column["name"],
+                column.get("color", "#6b7280"),
+                int(column.get("position", 0)),
+                column.get("label", ""), column.get("aliases", ""),
+                column.get("kind", "flow"),
+                1 if column.get("in_focus") else 0,
+            ),
+        )
+
+
+def delete_board_column(workspace_id: int, key: str) -> None:
+    with get_db() as conn:
+        conn.execute(
+            "DELETE FROM board_columns WHERE workspace_id = ? AND key = ?",
+            (workspace_id, key),
+        )
+
+
+def clear_board_columns(workspace_id: int) -> None:
+    with get_db() as conn:
+        conn.execute(
+            "DELETE FROM board_columns WHERE workspace_id = ?",
+            (workspace_id,),
+        )
+
+
+def count_column_cards(workspace_id: int, key: str) -> int:
+    with get_db() as conn:
+        row = conn.execute(
+            "SELECT COUNT(*) AS n FROM board_state "
+            "WHERE workspace_id = ? AND column_name = ?",
+            (workspace_id, key),
+        ).fetchone()
+    return int(row["n"]) if row else 0
+
+
+def migrate_column_cards(
+    workspace_id: int, from_key: str, to_key: str
+) -> int:
+    """Move every card of a column to another (column deletion).
+
+    Positions are appended after the target column's current
+    maximum, per repository and connection.
+    """
+    with get_db() as conn:
+        rows = conn.execute(
+            "SELECT connection_id, repo_full_name, issue_number "
+            "FROM board_state WHERE workspace_id = ? AND column_name = ? "
+            "ORDER BY position, issue_number",
+            (workspace_id, from_key),
+        ).fetchall()
+        for row in rows:
+            nxt = conn.execute(
+                "SELECT COALESCE(MAX(position), -1) + 1 AS p FROM board_state "
+                "WHERE workspace_id = ? AND connection_id = ? "
+                "AND repo_full_name = ? AND column_name = ?",
+                (
+                    workspace_id, row["connection_id"],
+                    row["repo_full_name"], to_key,
+                ),
+            ).fetchone()
+            conn.execute(
+                "UPDATE board_state SET column_name = ?, position = ?, "
+                "updated_at = datetime('now') WHERE workspace_id = ? "
+                "AND connection_id = ? AND repo_full_name = ? "
+                "AND issue_number = ?",
+                (
+                    to_key, nxt["p"], workspace_id, row["connection_id"],
+                    row["repo_full_name"], row["issue_number"],
+                ),
+            )
+    return len(rows)