fix(session): require config-backed mutation authority and workspace-bound targets (#714)

Close the #714 remediation gap left at 943d402 where env-only mutation
profiles, REMOTES Timesheet defaults treated as explicit caller input, and
machine-dependent Git remotes produced false greens.

- Fail closed when mutations lack a config-backed profile with non-empty
  allowed_repositories; env ops cannot invent mutation authority.
- Preserve omitted-vs-explicit org/repo provenance through the mutation
  gate; omitted targets bind to the verified workspace repository.
- Prefer workspace-aligned Git remotes over historical Timesheet defaults
  in MCP _resolve and CLI resolve_remote.
- Centralize deterministic config-backed mutation fixtures; migrate
  mutation tests off env-only authority without weakening security
  assertions.

Full suite: 2744 passed, 6 skipped.

gitea_auth.py

@@ -182,11 +182,51 @@ def get_auth_header(host):
 
 def resolve_remote(args):
     """Given parsed argparse args with --remote/--host/--org/--repo,
-    return (host, org, repo) with overrides applied."""
+    return (host, org, repo) with overrides applied.
+
+    #714 / #530: when the caller omits org and/or repo, prefer the
+    workspace-aligned git remote over REMOTES defaults (e.g. bare
+    ``--remote prgs`` must not force Timesheet when the checkout is
+    Gitea-Tools). Explicit --org/--repo always win.
+    """
     profile = REMOTES[args.remote]
     host = args.host or profile["host"]
-    org = args.org or profile["org"]
-    repo = args.repo or profile["repo"]
+    org_explicit = getattr(args, "org", None) is not None
+    repo_explicit = getattr(args, "repo", None) is not None
+    org = args.org if org_explicit else profile["org"]
+    repo = args.repo if repo_explicit else profile["repo"]
+    if not org_explicit or not repo_explicit:
+        try:
+            import remote_repo_guard
+            import subprocess
+            # Prefer the named remote URL when present; fall back to origin.
+            url = None
+            for remote_name in (args.remote, "origin"):
+                try:
+                    proc = subprocess.run(
+                        ["git", "remote", "get-url", remote_name],
+                        capture_output=True,
+                        text=True,
+                        timeout=5,
+                        check=False,
+                    )
+                    if proc.returncode == 0 and (proc.stdout or "").strip():
+                        url = proc.stdout.strip()
+                        break
+                except Exception:
+                    continue
+            # Allow tests to inject a deterministic remote URL without Git.
+            env_url = os.environ.get("GITEA_TEST_WORKSPACE_REMOTE_URL")
+            if env_url:
+                url = env_url
+            parsed = remote_repo_guard.parse_org_repo_from_remote_url(url)
+            if parsed:
+                if not org_explicit:
+                    org = parsed[0]
+                if not repo_explicit:
+                    repo = parsed[1]
+        except Exception:
+            pass
     return host, org, repo