stack: Telemetrie-Default nach Installationsform, Byte-Deckel und Session-Retention (schliesst #55)

Files changed:
- .gitea/workflows/ci.yml
- .gitignore
- CHANGES.md
- EVALS.md
- INSTALL-MCP.md
- INSTALL.md
- VERSION
- instructions/setup-instance.md
- reports/CONTRACT.md
- tools/CONTRACT.md
- tools/chemenu/commands/doctor.py
- tools/chemenu/config.py
- tools/chemenu/mcp/server.py
- tools/chemenu/telemetry/policy.py
- tools/chemenu/telemetry/schema.py
- tools/chemenu/telemetry/writer.py
- tools/chemenu/tests/conftest.py
- tools/chemenu/tests/test_doctor.py
- tools/chemenu/tests/test_mcp_server.py
- tools/chemenu/tests/test_telemetry_emit.py
- tools/chemenu/tests/test_telemetry_policy.py
- tools/chemenu/version.py

tools/chemenu/commands/doctor.py

@@ -345,6 +345,37 @@ def check_generated_files() -> Check:
     return Check("generated-files", "OK", "kb/index.md, kb/log.md, kb/provenance.md present")
 
 
+def check_telemetry() -> Check:
+    """Whether tracing is on for this checkout, why, and how full its two caps
+    are.
+
+    Never `FAIL`s, the same line `check_publish_remotes` and
+    `check_environment` draw: both an enabled and a disabled tree are
+    legitimate states, and a `FAIL` would make one of them mandatory by the
+    back door. The tree walk below is fine here - `doctor` is not a hot path,
+    unlike the `stat` `emit()` does on every append.
+    """
+    from chemenu.telemetry import policy as telemetry_policy
+    from chemenu.telemetry import reader
+    from chemenu.telemetry.writer import TRACE_FILE, trace_root
+
+    pol = telemetry_policy.resolve(config.ROOT)
+    root = trace_root()
+    session_count = len(reader.sessions(root))
+    total_bytes = (
+        sum(f.stat().st_size for f in root.glob(f"*/{TRACE_FILE}") if f.is_file())
+        if root.exists()
+        else 0
+    )
+    state = "on" if pol.enabled else "off"
+    return Check(
+        "telemetry", "OK",
+        f"{state} ({pol.reason}); {session_count}/{pol.keep_sessions} session(s), "
+        f"{total_bytes:,} byte(s) under {rel_path(root)} "
+        f"(cap {pol.max_session_bytes:,} byte(s)/session)",
+    )
+
+
 def check_session_id() -> Check:
     import os
 
@@ -449,6 +480,7 @@ def run_doctor() -> list[Check]:
         check_publish_remotes(),
         check_generated_files(),
         check_session_id(),
+        check_telemetry(),
     ]
     return checks
 
@@ -458,7 +490,8 @@ def doctor_command(
 ):
     """Check that this instance is correctly configured: dependencies, author,
     git identity/remote, published skills, structure, personalization, KB
-    conventions, generated files, and session scoping. Read-only. Exits 1 only
+    conventions, generated files, session scoping, and telemetry state.
+    Read-only. Exits 1 only
     if a check FAILs."""
     checks = run_doctor()