docs: complete claude-opus-4-7 bump in installation, matching, and overview guides

Sed-based bulk replace only touched hyphenated IDs (claude-opus-4-6)
but the tutorial prose and comparison tables used the dotted human
form 'Claude Opus 4.6' / 'Opus 4.6'. Sync those occurrences to 4.7
in:

- docs/guide/installation.md (model families table + Sisyphus tutorial)
- docs/guide/agent-model-matching.md (recommended-model table)
- docs/guide/overview.md (three references to Opus default)

Without this commit, users following the installation guide would be
told Sisyphus 'strongly recommends Opus 4.6' while the plugin itself
already routes to Opus 4.7.

docs/guide/overview.md

@@ -82,11 +82,11 @@ Sisyphus is your main orchestrator. He plans, delegates to specialists, and driv
 
 **Recommended models:**
 
-- **Claude Opus 4.6** — Best overall experience. Sisyphus was built with Claude-optimized prompts.
+- **Claude Opus 4.7** — Best overall experience. Sisyphus was built with Claude-optimized prompts.
 - **Kimi K2.5** — Great Claude-like alternative. Many users run this combo exclusively.
 - **GLM 5** — Solid option, especially via Z.ai.
 
-Sisyphus works best on Claude Opus 4.6, Kimi K2.5, and GLM 5. GPT-5.4 now has a dedicated prompt path, but older GPT models are still a poor fit and should route to Hephaestus instead.
+Sisyphus works best on Claude Opus 4.7, Kimi K2.5, and GLM 5. GPT-5.4 now has a dedicated prompt path, but older GPT models are still a poor fit and should route to Hephaestus instead.
 
 ### Hephaestus: The Legitimate Craftsman
 
@@ -219,7 +219,7 @@ You can override specific agents or categories in your config:
 
 **Claude-like models** (instruction-following, structured output):
 
-- Claude Opus 4.6, Claude Haiku 4.5
+- Claude Opus 4.7, Claude Haiku 4.5
 - Kimi K2.5 — behaves very similarly to Claude
 - GLM 5 — Claude-like behavior, good for broad tasks