docs(v1.87.0): migrate CLAUDE.md policy state + flip Current pinning (Wave X)

[songkuan-zheng]

Tier classification

• A — Company-specific logic (litellm_extras/ only)
• B — Internal infra / branding (CI, Dockerfile, e2e, internal navbar version)
• C — Universal bug fix in litellm/ core
• D — Universal mechanism + company opinion in litellm/ core

If Tier C or D, did you try upstream first?

• N/A — internal policy doc.

Summary

Ports the policy state from ship/v1.83.10 to ship/v1.87.0 and flips the
Current pinning block to v1.87.0. After this PR ship/v1.87.0 owns
the full CLAUDE.md (Tier classification, Current pinning, Upstream sync
cadence) + scripts/upstream-sync-check.sh +
.github/pull_request_template.md.

Why this exists

Wave 2 (#47) cherry-picked f67766f6bf which carried a 50-line
skeleton CLAUDE.md from before our policy work landed. PRs #43, #45
later added Tier classification, Current pinning, and Upstream sync
cadence on ship/v1.83.10 — but those never crossed over. PR #44 added
scripts/upstream-sync-check.sh on ship/v1.83.10 only.

This PR closes the gap.

Verification

```bash
bash scripts/upstream-sync-check.sh --no-fetch

Reports:

Upstream sync check — pinned to v1.87.0 ← auto-discovered from new CLAUDE.md

== 1. Missed backports on v1.87.x ==

✓ Nothing new on v1.87.x.

== 2. Newer minor lines stabilized since pin ==

✓ No newer minor lines published a stable tag.

== 3. Volume on upstream/main since v1.87.0 ==

Commits on upstream/main not in v1.87.0: 100

== 4. Security-flagged commits on upstream/main since v1.87.0 ==

✓ No security-flagged subjects matched.

```

Changes

• CLAUDE.md (heavy):
  • Current pinning flipped: v1.87.0 (Upstream pin / Ship / Sync /
    Internal release pattern).
  • Branching strategy example column updated to v1.87.0 /
    ship/v1.87.0 / internal/v1.87.0-stable. The pin tag column
    documents both forms ( vX.Y.Z post-1.84.0, vX.Y.Z-stable for
    older pins) so historical refs still parse.
  • Cutting an internal release example becomes v1.87.0-internal.1
    (release-tag.sh contract — N restarts at 1 under a new pin).
  • Upstream sync cadence patch-tag example covers both new and
    legacy formats.
  • git tag -l 'v1.87.0-internal.*' for the latest-release lookup.
• scripts/upstream-sync-check.sh: copied verbatim from
  ship/v1.83.10. Auto-discovers the new pin via CLAUDE.md regex.
• .github/pull_request_template.md: copied verbatim — Tier
  classification checkbox stays consistent across both ship branches
  during the transition window.

Phase 2 status after this PR

Of the 7 planned waves, 6 complete:

Wave	Status
1: CI workflows	✅
2: e2e harness core	✅
2.5: in-network mock provider	✅
3: PublicReqMiddleware + small UI fix	✅
4: low-conflict Tier C bug fixes	✅
5a–d: U-class architectural decisions	✅
X: CLAUDE.md migration	🔄 (this PR)
6: hot-path (WARN/ERROR + router + thinking-signature + user.models)	⏳
7: UI 401 + final UI rebuild	⏳

Once this lands, ship/v1.87.0 fully owns the same policy surface as
ship/v1.83.10 and can be safely operated against until Wave 6/7 close
out the remaining functional ports.

Type

📖 Documentation