docs(specs): plan a template rule that shares templated positions

Record the outcome, requirements, non-goals, plan and tasks for
prefix-variance, an opt-in environment-manifest rule that templates a
literal segment with the parameter another tool already uses at that
position, so a session's writes to one entity share the read's template.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/specs/agent-environments/prefix-variance/plan.md

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+# Plan
+
+1. Move tool naming (`parameterNames`, `pathTemplate`, `toolName`,
+   `compareTools`) from `environmentManifestRules.ts` to a new
+   `environmentManifestNames.ts`, so the rules module has room for the rule.
+2. Add `prefix-variance` to `TEMPLATE_RULES`. A `prefix-variance` parameter
+   records the rule it shares (`sharedRule`), which names it and keys it.
+3. Add the pass after `sibling-variance`: walk positions in order, index the
+   opt-in parameters at each position by their preceding parts, template
+   qualifying literals, then rebucket by naming key, keeping a tool's own rule
+   for each merged position.
+4. Share the 32-segment split between the three comparing passes and list the
+   segment-limited rules once for the limitation.
+5. Document the rule in the view schema description and in
+   `docs/web-network-captures.md`.
+6. Tests: shared positions across methods and depths, the spelling condition,
+   merges that keep a tool's own rule, pairs, format-rule positions and the
+   segment limit.

docs/specs/agent-environments/prefix-variance/spec.md

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+# Share templated positions across tools
+
+Issue: https://github.com/morluto/rea/issues/4933
+
+## Outcome
+
+A session usually edits one scratch entity: it creates it, then updates and
+deletes it at a fixed path such as `/api/v1/collections/0RZ576QZQA5KG`. The
+manifest templates a segment only when sibling routes of the same method vary
+there, so those writes stay literal tools (`patch_collections_0rz576qzqa5kg`)
+even though the reads of the same collection were templated as
+`/api/v1/collections/{collection_id}`. A literal write tool addresses one
+entity that may not exist in a later state, and nothing can model its effect.
+
+A new opt-in template rule, `prefix-variance`, templates such a literal with
+the parameter another tool already uses at that position, so the write becomes
+`patch_collections_by_collection_id` on the same template as the read.
+
+## Requirements
+
+- `prefix-variance` applies only when listed, after every other opt-in rule, so
+  it can share the parameters they produce.
+- A literal at position `p` is templated when another tool on the same origin,
+  of any method and any segment count, has a parameter at `p` from one of the
+  other opt-in rules, after the same preceding parts. Parameters in the
+  preceding parts compare by the rule that names them, so a position templated
+  by `prefix-variance` matches the parameter it shares.
+- The literal qualifies when it is one of the values any such tool observed at
+  that position, or when it carries a digit and has the length and character
+  classes (digits, lower case, upper case, each other character) of one of
+  them. An empty literal, a stop word or a `v1`-style version never qualifies.
+- Positions templated by the four format rules are never shared, so
+  `/api/teams/{numeric}` still absorbs no literal.
+- The parameter takes the name of the parameter it shares (`collection_id`,
+  `uid`, a pair's `_namespace` and `_name`) and is labelled `prefix-variance`.
+- Tools whose routes now match, by method and by the rule that names each
+  parameter, merge. A merged parameter keeps the rule of a tool that templated
+  that position itself, when one did.
+- Like the sibling rules, it compares routes of at most 32 segments and says so
+  in a limitation when a longer route exists.
+
+## Non-goals
+
+- No change to the default rules or to any other rule: manifests that do not
+  list `prefix-variance` are byte-for-byte unchanged.
+- No templating from response bodies, such as an id a create returned; the
+  manifest reads request lines only.
+- No change to which groups are excluded: a write whose response has no body
+  or content type outside `/api/` is still excluded as `non-json`.

docs/specs/agent-environments/prefix-variance/tasks.md

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+# Tasks
+
+- [x] Record the outcome, requirements and non-goals.
+- [x] Move tool naming into its own module.
+- [x] Add the `prefix-variance` rule, its names, its merge and its limitation.
+- [x] Document the rule in the schema and the capture guide.
+- [x] Add rule tests.
+- [x] Run static, formatting, duplication, documentation and test gates.
+- [x] Project the 51 corpus captures with and without the rule and record the results.