feat: make mine-tasks codehost-agnostic with git-only fallback

The skill now works with any git host: GitHub, GitLab, Bitbucket,
Azure DevOps, Gitea/Forgejo, self-hosted instances, or plain local
repos with no remote API at all.

Key changes:

- Add Host Adapter Reference section with per-host CLI/API commands
  for: listing merged MRs, getting diffs, getting metadata, getting
  linked issues, clone URLs + auth, repo validation, contributor
  discovery

- Host auto-detection from URL patterns (github.com, gitlab.com,
  bitbucket.org, dev.azure.com, self-hosted). Prompts for platform
  type when ambiguous.

- git-only fallback mode: mines from git log (merge commits + commit
  messages), uses git diff for patches, git log --format='%an' for
  contributors. Works with zero API access.

- Clone URLs and auth patterns are per-host:
  GitHub: x-access-token, GitLab: oauth2, Bitbucket: x-token-auth,
  Azure: user:token. All use generic "repo_token" secret name.

- Contributor discovery: git log frequency as primary (universal)
  method, host-specific reviewer APIs as enrichment

- Mixed-host support: repos from different hosts in the same eval,
  each gets its own adapter and auth

- Removed GitHub Copilot as MCP provider option (host-specific),
  kept Sourcegraph (works with any host) + Custom + Placeholder

- Updated terminology: "PR" → "MR/PR" throughout, host-neutral
  language in summaries and output

Also regenerates script registry and index to fix pre-existing
staleness.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sjarmak

docs/ops/SCRIPT_INDEX.md

@@ -176,6 +176,7 @@ Generated from `scripts/registry.json` by `scripts/generate_script_index.py`.
 - `scripts/backfill_size_metadata.py` [one_off] - Historical one-off script: backfill size metadata.
 - `scripts/backfill_triage_from_manifest.py` [one_off] - Historical one-off script: backfill triage from manifest.
 - `scripts/check_harness_readiness.py` - Utility script for check harness readiness.
+- `scripts/collect_repo_cloc.py` - Utility script for collect repo cloc.
 - `scripts/compare_contextbench_results.py` - Utility script for compare contextbench results.
 - `scripts/compare_old_new_ground_truth.py` - Utility script for compare old new ground truth.
 - `scripts/compute_analysis_ir_metrics.py` - Utility script for compute analysis ir metrics.

scripts/registry.json

@@ -210,6 +210,14 @@
       "language": "python",
       "summary": "Pre-run infrastructure readiness checker (tokens, Docker, disk, Harbor CLI)."
     },
+    {
+      "name": "collect_repo_cloc.py",
+      "path": "scripts/collect_repo_cloc.py",
+      "category": "misc",
+      "status": "maintained",
+      "language": "python",
+      "summary": "Utility script for collect repo cloc."
+    },
     {
       "name": "compare_configs.py",
       "path": "scripts/compare_configs.py",
@@ -1667,7 +1675,7 @@
     "infra_mirrors": 20,
     "library_helpers": 7,
     "migration": 4,
-    "misc": 90,
+    "misc": 91,
     "qa_quality": 10,
     "submission_reporting": 7,
     "task_creation_selection": 13,