ci: SessionStart hook to auto-provision Agda toolchain on the web

Adds .claude/hooks/session-start.sh (+ .claude/settings.json registration)
so Claude Code on the web auto-runs the idempotent scripts/provision-agda.sh
at session start, making 'agda proofs/agda/All.agda' / Smoke.agda typecheck
without manual setup. Web-only (guards on CLAUDE_CODE_REMOTE); synchronous so
the toolchain is ready before the agent loop.

.gitignore: switch '.claude/' to '.claude/*' with negations so the shared
hook + settings are tracked while personal Claude config stays ignored.

https://claude.ai/code/session_01VwbFNQJw23tW8tqM7utWku

Author: claude

.claude/hooks/session-start.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: MPL-2.0
+# SessionStart hook: provision the Agda proof-checker toolchain so Claude Code
+# on the web can typecheck this repo (agda proofs/agda/All.agda, Smoke.agda).
+#
+# Thin wrapper around scripts/provision-agda.sh (idempotent). Web-only; local
+# developers manage their own toolchain. Synchronous so the toolchain is ready
+# before the agent loop starts.
+set -euo pipefail
+
+# Only provision in the remote (web) environment.
+if [ "${CLAUDE_CODE_REMOTE:-}" != "true" ]; then
+  exit 0
+fi
+
+exec bash "${CLAUDE_PROJECT_DIR:-$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)}/scripts/provision-agda.sh"

.claude/settings.json

@@ -0,0 +1,14 @@
+{
+  "hooks": {
+    "SessionStart": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "$CLAUDE_PROJECT_DIR/.claude/hooks/session-start.sh"
+          }
+        ]
+      }
+    ]
+  }
+}

.gitignore

@@ -1,6 +1,9 @@
 *.agdai
 _build/
-.claude/
+# Ignore personal Claude config but share the SessionStart toolchain hook.
+.claude/*
+!.claude/hooks/
+!.claude/settings.json
 .agda/
 
 # direnv / nix local cache