Share the java-tdd-guide pointer file across the four repositories

workspace/CLAUDE.md says every sibling repository carries
.claude/skills/java-tdd-guide/SKILL.pointer.md, the marker that tells a
human reader (and any drift tooling) where the canonical Java TDD skill
lives and why the workspace repository must be in the session scope.
Only BitcoinAddressFinder and streambuffer had it, and the two copies
differed by one BitcoinAddressFinder-specific paragraph.

The file now exists in all four repositories with one byte-identical
content (streambuffer's, which names no repository) and is listed in
every .github/shared-files.sha256, so the shared-files job keeps it
equal from here on. BitcoinAddressFinder's extra paragraph only
cross-referenced its own `tdd` skill, whose own description already
says it delegates to the generic guide and adds project context; the
pointer carries nothing repo-specific any more. In java-llama.cpp the
path is added to REUSE.toml's markdown list; the other three cover it
through their `**.md` annotation already.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AytmJF9faEiQEVt6eetQS2

Author: claude

.github/shared-files.sha256

@@ -37,6 +37,7 @@ ab45f5c102b47dd16c325d4d9c283d158ba90c05f484eac45b2767885c4462f9  .github/signin
 0f08122e597f93dbbdc9c80e88984b4bf4738951d5902813df3d4640cdb11bac  .github/ISSUE_TEMPLATE/feature_request.md
 ebfcc0adf59f5858bbe4dc077c906304a197f72a55256f0d5aac669bee5e871f  .github/PULL_REQUEST_TEMPLATE.md
 f2a516d98a4287486dac82fc2c1293d81e3a4a1087e3ace934da0af5caaeace5  CODE_OF_CONDUCT.md
+b191c691d333249de1780e474817446cd94262e0bfa87e27cb6e412865f90943  .claude/skills/java-tdd-guide/SKILL.pointer.md
 074e6e32c86a4c0ef8b3ed25b721ca23aca83df277cd88106ef7177c354615ff  LICENSES/Apache-2.0.txt
 b05785f9f18e6716bab63424b11454513b9943a222595b70411009202fc592b5  LICENSES/MIT.txt
 edc34bc287c32b4d7ff970c0dd7a25e7d724cdd2775ef2b65aaccccd49c733c8  .editorconfig