feat(web): Core Refactor Phase A — extract sampling and cache modules; add adaptive TTL + eviction heuristics, Redis PoC, and metrics wiring. Tests added for TTL, eviction, exports, splash-adaptive, card index, and service worker. Docs+roadmap updated.

.github/workflows/editorial_governance.yml

@@ -49,4 +49,65 @@ jobs:
         uses: actions/upload-artifact@v4
         with:
           name: ratchet-proposal
-          path: ratchet_proposal.json
+          path: ratchet_proposal.json
+      - name: Post ratchet proposal PR comment
+        if: github.event_name == 'pull_request'
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const fs = require('fs');
+            const markerStart = '<!-- ratchet-proposal:description-fallback -->';
+            const markerEnd = '<!-- end-ratchet-proposal -->';
+            let proposal = {};
+            try { proposal = JSON.parse(fs.readFileSync('ratchet_proposal.json','utf8')); } catch(e) { proposal = {error: 'Failed to read ratchet_proposal.json'}; }
+            function buildBody(p) {
+              if (p.error) {
+                return `${markerStart}\n**Description Fallback Ratchet Proposal**\n\n:warning: Could not compute proposal: ${p.error}. Ensure history file exists and job built with EDITORIAL_INCLUDE_FALLBACK_SUMMARY=1.\n${markerEnd}`;
+              }
+              const curTotal = p.current_total_ceiling;
+              const curPct = p.current_pct_ceiling;
+              const propTotal = p.proposed_total_ceiling;
+              const propPct = p.proposed_pct_ceiling;
+              const changedTotal = propTotal !== curTotal;
+              const changedPct = propPct !== curPct;
+              const rationale = (p.rationale && p.rationale.length) ? p.rationale.map(r=>`- ${r}`).join('\n') : '- No ratchet conditions met (headroom not significant).';
+              const testFile = 'code/tests/test_theme_description_fallback_regression.py';
+              let updateSnippet = 'No changes recommended.';
+              if (changedTotal || changedPct) {
+                updateSnippet = [
+                  'Update ceilings in regression test (lines asserting generic_total & generic_pct):',
+                  '```diff',
+                  `- assert summary.get('generic_total', 0) <= ${curTotal}, summary`,
+                  `+ assert summary.get('generic_total', 0) <= ${propTotal}, summary`,
+                  `- assert summary.get('generic_pct', 100.0) < ${curPct}, summary`,
+                  `+ assert summary.get('generic_pct', 100.0) < ${propPct}, summary`,
+                  '```' ].join('\n');
+              }
+              return `${markerStart}\n**Description Fallback Ratchet Proposal**\n\nLatest snapshot generic_total: **${p.latest_total}**  | median recent generic_pct: **${p.median_recent_pct}%** (window ${p.records_considered})\n\n| Ceiling | Current | Proposed |\n|---------|---------|----------|\n| generic_total | ${curTotal} | ${propTotal}${changedTotal ? ' ←' : ''} |\n| generic_pct | ${curPct}% | ${propPct}%${changedPct ? ' ←' : ''} |\n\n**Rationale**\n${rationale}\n\n${updateSnippet}\n\nHistory-based ratcheting keeps pressure on reducing generic fallback descriptions. If adopting the new ceilings, ensure editorial quality remains stable.\n\n_Analysis generated by ratchet bot._\n${markerEnd}`;
+            }
+            const body = buildBody(proposal);
+            const { data: comments } = await github.rest.issues.listComments({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.issue.number,
+              per_page: 100
+            });
+            const existing = comments.find(c => c.body && c.body.includes(markerStart));
+            if (existing) {
+              await github.rest.issues.updateComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                comment_id: existing.id,
+                body
+              });
+              core.info('Updated existing ratchet proposal comment.');
+            } else {
+              await github.rest.issues.createComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: context.issue.number,
+                body
+              });
+              core.info('Created new ratchet proposal comment.');
+            }