chore(devtools): publish workflow mirror (CTX-0012)

[Xuepoo]

Priority: P1 | Area: devtools | Labels: chore,area:devtools,P1 | Milestone: v0.1.0 | Task: CTX-0012

Ports the proven CTX-0012 pilot template (bitty-terminal/bitty-website#17, commit 96a3cbd) verbatim, parametrizing only the source-repo default.

Changes (scope: scripts/ + justfile only)

• scripts/publish-ctxpack.sh (parametrized: WORKFLOW_SOURCE_REPO default bitty-mcp; mirror bitty-mcp-workflow derives automatically; generic source.json keys repo/repo_commit/repo_branch)
• scripts/publish-ctxpack-redact.py (verbatim, diff-identical to pilot)
• scripts/publish-ctxpack-selftest.sh (verbatim, diff-identical to pilot)
• justfile: workflow-publish / workflow-publish-dry stanzas

Evidence

• just check: markdownlint 0 issues, prettier all files pass
• just workflow-publish-dry: PASS (round-trip all 16 tables, redaction fixture PASS)
• Protocol/security/interop impact: none (tooling only, no product code)

Closes #15