docs(skills): drop references to PYSPARK_ALIGNMENT_PLAN.md

The plan file is a working document, not a committed artifact, so skills
must not point at it. Inline the one substantive reference (the
"deferred to follow-up PRs" callout in make-pythonic) and drop the
cross-cutting pointer from check-upstream.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: timsaucer

.ai/skills/check-upstream/SKILL.md

@@ -244,10 +244,6 @@ namespace while pyspark's single-positional form continues to work.
    aliases another function's Rust binding.
 4. Report functions that are missing from the Python spark namespace.
 
-**Cross-cutting reference:** The longer-form roadmap for spark coverage
-lives in `PYSPARK_ALIGNMENT_PLAN.md` (root of repo). Use it as the source
-of truth for which gaps are intentionally deferred vs. ready to land.
-
 ### 9. `__all__` Hygiene (functions.py and functions/spark.py)
 
 Independent of upstream parity, also flag public `def` symbols in

.ai/skills/make-pythonic/SKILL.md

@@ -44,8 +44,8 @@ still on-brand:
   takes `format: str | Column`; the spark wrapper already auto-promotes a
   plain `str` to a literal — keep parity.
 - **Strictly additive optional kwargs** that pyspark also has (e.g.
-  `like(escapeChar=...)`). These belong in the [PYSPARK_ALIGNMENT_PLAN.md]
-  follow-up PRs, not in a make-pythonic pass.
+  `like(escapeChar=...)`). These belong in pyspark-alignment follow-up
+  PRs, not in a make-pythonic pass.
 
 If the user explicitly scopes to "spark", validate parity with pyspark
 rather than applying generic coercion.