docs: correct drifted counts, reconcile the v3.8.50 changelog and gate the free-forever number (#10433)

Audit of every numeric claim in the README, AGENTS.md and the README SVGs against
live code, plus a changelog/credit reconciliation over the full v3.8.50 cycle.

Corrected numbers (all measured, not estimated):

- Provider circuit breaker thresholds were scaled up in code for 500+ connection
  deployments (`providerFailureThreshold`: OAuth 3 -> 10, API key 5 -> 15) but the
  docs still published the pre-scale values. Fixed in AGENTS.md (now a table that
  also separates the provider-level threshold from the per-connection one and lists
  the provider cooldowns), in the README alt text and inside resilience-layers.svg
  (visible label and aria-label).
- "40+ free forever" was unsourced. Measured from the free-tier catalog as every
  provider whose free access renews or needs no key (recurring-monthly, -daily,
  -uncapped, -credit, keyless; one-time signup credits and discontinued pools
  excluded): 56. Updated in the README and promise-pillars.svg.
- Cycle-evolution table: v3.8.49 shipped 290 providers, not 291, and the model row
  compared the v3.8.49 free-tier catalog (516) against today's full catalog. Both
  columns now use the same metric - distinct documented models, 1185 -> 1202.
- Tech-stack row: 95 domain modules -> 117.

The free-forever count is now enforced by check:docs-counts so it cannot drift
again; it is derived from freeType in the live catalog, like every other gated
number.

Changelog reconciliation (`scripts/release/list-uncovered-commits.mjs`):
uncovered cycle commits drop from 149 to 62. 75 user-facing commits gained a bullet
with author attribution, the 45 ref-less direct pushes and 29 chore/ci/test/docs
commits were consolidated into rollup bullets, and the contributors table grew from
147 to 161 rows - 14 contributors who had landed work with no credit at all
(including @amartinawi, @pacocartones and @excessivechaos) are now credited.
The remaining 62 carry no PR/issue ref, which is the ceiling of ref-based coverage.

CHANGELOG.md and its i18n mirrors are added to .prettierignore: check:changelog-
integrity compares base bullets as exact strings, and Prettier normalizes markdown
emphasis inside them (*from* -> _from_), so any PR that staged the changelog turned
the merge-integrity job red. scripts/release/* is the changelog's formatter of
record, the same precedent already used for ENVIRONMENT.md and PROVIDER_REFERENCE.md.

Co-authored-by: Xiangzhe <bakryun0718@proton.me>

scripts/check/check-docs-counts-sync.mjs

@@ -175,10 +175,15 @@ function readCodeFacts() {
     "for(const x of (t?.scopes||[]))sc.add(x);",
     "const t=computeFreeModelTotals();const cli=Object.values(CLI_TOOLS);",
     "const by=(c)=>cli.filter(x=>x.category===c).length;",
+    // "Free forever" = every provider whose free access renews or needs no key at all.
+    // one-time-initial (signup credits) and discontinued pools are excluded on purpose.
+    "const FOREVER=new Set(['recurring-monthly','recurring-daily','recurring-uncapped',",
+    "'recurring-credit','keyless']);",
+    "const ff=new Set();for(const m of t.perModel)if(FOREVER.has(m.freeType))ff.add(m.provider);",
     'console.log("@@"+JSON.stringify({freeSteady:t.steadyRecurringTokens,',
     "freeFirst:t.firstMonthRealisticTokens,freePools:t.poolCount,engines:ENGINE_IDS.length,",
     "cliTotal:cli.length,cliCode:by('code'),cliAgent:by('agent'),",
-    "mcpTools:countUniqueMcpTools(cols),mcpScopes:sc.size,providers:pids.size}));",
+    "mcpTools:countUniqueMcpTools(cols),mcpScopes:sc.size,providers:pids.size,freeForever:ff.size}));",
   ].join("");
   const tmp = fs.mkdtempSync(path.join(os.tmpdir(), "docs-counts-"));
   try {
@@ -460,6 +465,10 @@ export function buildChecks() {
         ),
         claim(f.mcpScopes, "MCP scopes", { pattern: /(\d+) scopes/gi }, ["README.md", "AGENTS.md"]),
         claim(f.cliTotal, "CLI tools", { pattern: /(\d+) tools(?=\s*\(\d+ CLI)/gi }, ["README.md"]),
+        claim(f.freeForever, "free-forever providers", { pattern: /(\d+) free forever/gi }, [
+          "README.md",
+          "docs/diagrams/promise-pillars.svg",
+        ]),
       ];
     })(),
     {