feat: v0.7.0 — AgentDef provider/model + install --provider/--model/--no-config : résolution flag > agent > défaut, erreur si provider inconnu (liste du registre), warning si modèle absent, résolution affichée en résumé et au --dry-run (closes #90)

- Providers réels livrés dans le catalogue par défaut (anthropic★/openai/deepseek/google) + hints provider sur claude-code/deepseek-harness
- Suppression par null dans l'overlay : am providers remove écrit <nom>: null (merge traite null comme suppression, set_path remplace le null avant de descendre)
- Cascade @secret (#89) : le provider déclaré de l'agent prime sur default_provider

src/commands/install_cmd.rs

@@ -8,7 +8,15 @@ use crate::runner::SystemRunner;
 use anyhow::{anyhow, bail, Result};
 use std::collections::BTreeMap;
 
-pub fn run(app: &App, agent_name: &str, method_sel: Option<&str>, force: bool) -> Result<i32> {
+pub fn run(
+    app: &App,
+    agent_name: &str,
+    method_sel: Option<&str>,
+    force: bool,
+    provider: Option<&str>,
+    model: Option<&str>,
+    no_config: bool,
+) -> Result<i32> {
     let agent = require_agent(app, agent_name)?;
     let runner = SystemRunner::new(app.dry_run(), app.cli.verbose, &app.log);
 
@@ -38,6 +46,20 @@ pub fn run(app: &App, agent_name: &str, method_sel: Option<&str>, force: bool) -
     let methods = spec.all_methods();
     let method = select_method(&methods, method_sel)?;
 
+    // Provider/model resolution (issue #90): flag > agent.provider >
+    // settings.default_provider ; flag --model > agent.model >
+    // provider.default_model. Displayed in the summary (and by --dry-run).
+    let resolved = resolve_provider_config(app, agent, provider, model)?;
+    if no_config {
+        app.log
+            .info(crate::i18n::tr("--no-config : aucune configuration post-install"));
+    } else if !spec.configurable {
+        app.log.info(&crate::tr_fmt!(
+            "{} ne prend aucune configuration (install.configurable: false)",
+            agent.name
+        ));
+    }
+
     // Already installed?
     let existing = app.state.get(&agent.name).ok().flatten();
     if existing.is_some() && !force && !app.dry_run() {
@@ -138,10 +160,17 @@ pub fn run(app: &App, agent_name: &str, method_sel: Option<&str>, force: bool) -
     let entry = installers::make_entry(agent, method, &outcome, app);
     let version = entry.version.clone().unwrap_or_else(|| "unknown".to_string());
     app.state.set(&entry)?;
+    let mut args = vec![format!("method={}", method.kind)];
+    if let Some((p, m)) = &resolved {
+        args.push(format!("provider={p}"));
+        if let Some(m) = m {
+            args.push(format!("model={m}"));
+        }
+    }
     app.emit(
         &Event::now(EventKind::Install)
             .with_agent(agent.name.clone())
-            .with_args(vec![format!("method={}", method.kind)]),
+            .with_args(args),
     );
     crate::hooks::run_hooks(
         app,
@@ -161,3 +190,84 @@ pub fn run(app: &App, agent_name: &str, method_sel: Option<&str>, force: bool) -
     }
     Ok(0)
 }
+
+/// Resolve the provider + model of this install (issue #90) and print what
+/// will be configured. Returns (provider, model) when resolved.
+///
+/// Validation rules:
+/// - an explicit `--provider` that is not registered → error listing the
+///   registry (the user asked for it by name);
+/// - an agent-declared provider that is not registered → warning only
+///   (catalog metadata may reference a provider the user has not added yet);
+/// - a model absent from the provider's model list → warning, not blocking.
+fn resolve_provider_config(
+    app: &App,
+    agent: &AgentDef,
+    flag_provider: Option<&str>,
+    flag_model: Option<&str>,
+) -> Result<Option<(String, Option<String>)>> {
+    let flag_p = flag_provider.filter(|p| !p.is_empty());
+    let agent_p = agent.provider.as_deref().filter(|p| !p.is_empty());
+
+    // Explicit provider requested but not registered: hard error.
+    if let Some(p) = flag_p {
+        if crate::providers::get(&app.config, p).is_none() {
+            let known = crate::providers::names(&app.config);
+            let hint = if known.is_empty() {
+                "am providers add <nom> --base-url <url>".to_string()
+            } else {
+                known.join(", ")
+            };
+            bail!(crate::tr_fmt!(
+                "provider '{}' inconnu — providers enregistrés: {}",
+                p,
+                hint
+            ));
+        }
+    }
+    // Agent-declared provider not registered: warn (unless the user already
+    // overrode it with --provider, which was validated above).
+    if let Some(p) = agent_p {
+        if flag_p.is_none() && crate::providers::get(&app.config, p).is_none() {
+            app.log.warn(&crate::tr_fmt!(
+                "provider '{}' (déclaré par {}) non enregistré — voir: am providers add {} --base-url <url>",
+                p,
+                agent.name,
+                p
+            ));
+            return Ok(None);
+        }
+    }
+
+    let Some((pname, def, model)) = crate::providers::resolve_for(
+        &app.config,
+        agent.provider.as_deref(),
+        agent.model.as_deref(),
+        flag_provider,
+        flag_model,
+    ) else {
+        app.log.info(crate::i18n::tr(
+            "aucun provider configuré — voir: am providers add <nom> --base-url <url>",
+        ));
+        return Ok(None);
+    };
+
+    // Model not in the provider's list: warn, keep going.
+    if let Some(m) = model {
+        if !def.models.is_empty() && !def.models.iter().any(|x| x == m) {
+            app.log.warn(&crate::tr_fmt!(
+                "modèle '{}' absent de la liste du provider '{}' — modèles: {}",
+                m,
+                pname,
+                def.models.join(", ")
+            ));
+        }
+    }
+    let model_label = model.unwrap_or("-");
+    app.log.info(&crate::tr_fmt!(
+        "configuré avec le provider {} (modèle {})",
+        pname,
+        model_label
+    ));
+    Ok(Some((pname.to_string(), model.map(String::from))))
+}