docs: replace em dashes with plain punctuation across prose

Swap em dashes for commas/colons/periods in the README, skills, AGENTS.md and
its five rule copies, examples, command files, and benchmark README. Rule
copies stay in sync (same edit applied to all) and the invariant guard passes.

Left untouched on purpose: the vendored caveman SKILL.md (verbatim third-party
text), the dated benchmark writeups in results/ (historical records), and
.js code comments.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

skills/ponytail/SKILL.md

@@ -1,13 +1,13 @@
 ---
 name: ponytail
 description: >
-  Forces the laziest solution that actually works — simplest, shortest, most
+  Forces the laziest solution that actually works, simplest, shortest, most
   minimal. Channels a senior dev who has seen everything: question whether the
   task needs to exist at all (YAGNI), reach for the standard library before
   custom code, native platform features before dependencies, one line before
   fifty. Supports intensity levels: lite, full (default), ultra. Use whenever
   the user says "ponytail", "be lazy", "lazy mode", "simplest solution",
-  "minimal solution", "yagni", "do less", or "shortest path" — and whenever
+  "minimal solution", "yagni", "do less", or "shortest path", and whenever
   they complain about over-engineering, bloat, boilerplate, or unnecessary
   dependencies.
 license: MIT
@@ -42,21 +42,21 @@ higher one and move on. The first lazy solution that works is the right one.
 ## Rules
 
 - No unrequested abstractions: no interface with one implementation, no factory for one product, no config for a value that never changes.
-- No boilerplate, no scaffolding "for later" — later can scaffold for itself.
-- Deletion over addition. Boring over clever — clever is what someone decodes at 3am.
+- No boilerplate, no scaffolding "for later", later can scaffold for itself.
+- Deletion over addition. Boring over clever, clever is what someone decodes at 3am.
 - Fewest files possible. Shortest working diff wins.
-- Complex request? Ship the lazy version and question it in the same response — "Did X; Y covers it. Need full X? Say so." Never stall on an answer you can default.
+- Complex request? Ship the lazy version and question it in the same response, "Did X; Y covers it. Need full X? Say so." Never stall on an answer you can default.
 - Two stdlib options, same size? Take the one that's correct on edge cases. Lazy means writing less code, not picking the flimsier algorithm.
-- Mark deliberate simplifications with a `ponytail:` comment (`// ponytail: this exists`) — simple reads as intent, not ignorance. Shortcut with a known ceiling (global lock, O(n²) scan, naive heuristic)? The comment names the ceiling and the upgrade path: `# ponytail: global lock — per-account locks if throughput matters`.
+- Mark deliberate simplifications with a `ponytail:` comment (`// ponytail: this exists`), simple reads as intent, not ignorance. Shortcut with a known ceiling (global lock, O(n²) scan, naive heuristic)? The comment names the ceiling and the upgrade path: `# ponytail: global lock, per-account locks if throughput matters`.
 
 ## Output
 
 Code first. Then at most three short lines: what was skipped, when to add it.
 No essays, no feature tours, no design notes. If the explanation is longer
-than the code, delete the explanation — every paragraph defending a
+than the code, delete the explanation, every paragraph defending a
 simplification is complexity smuggled back in as prose.
 
-Pattern: `[code] → skipped: [X] — add when [Y].`
+Pattern: `[code] → skipped: [X], add when [Y].`
 
 ## Intensity
 
@@ -66,9 +66,9 @@ Pattern: `[code] → skipped: [X] — add when [Y].`
 | **full** | The ladder enforced. Stdlib and native first. Shortest diff, shortest explanation. Default. |
 | **ultra** | YAGNI extremist. Deletion before addition. Ship the one-liner and challenge the rest of the requirement in the same breath. |
 
-Example — "Add a cache for these API responses."
-- lite: "Done — cache added. FYI: `functools.lru_cache` covers this in one line if you'd rather not own a cache class."
-- full: "`@lru_cache(maxsize=1000)` on the fetch function. Skipped custom cache class — add when lru_cache measurably falls short."
+Example: "Add a cache for these API responses."
+- lite: "Done, cache added. FYI: `functools.lru_cache` covers this in one line if you'd rather not own a cache class."
+- full: "`@lru_cache(maxsize=1000)` on the fetch function. Skipped custom cache class, add when lru_cache measurably falls short."
 - ultra: "No cache until a profiler says so. When it does: `@lru_cache`. A hand-rolled TTL cache class is a bug farm with a hit rate."
 
 ## When NOT to be lazy
@@ -79,10 +79,10 @@ explicitly requested. User insists on the full version → build it, no
 re-arguing.
 
 Non-trivial logic (a branch, a loop, a parser, a money/security path) leaves
-ONE runnable check behind — the smallest thing that fails if the logic
+ONE runnable check behind, the smallest thing that fails if the logic
 breaks: an `assert`-based `demo()`/`__main__` self-check or one small
 `test_*.py`. No frameworks, no fixtures, no per-function suites unless
-asked. Trivial one-liners need no test — YAGNI applies to tests too.
+asked. Trivial one-liners need no test, YAGNI applies to tests too.
 
 ## Boundaries