docs: fix broken links and image paths in landing page

- landing.mdx: convert file links from /install/index.md format to /docs/install web routes
- landing.mdx: fix screenshot image paths from @site/../docs to ../../../docs (correct relative path)
- landing.mdx: standardize link format to /docs/... for consistency
- docs/index.mdx: use GitHub URL for CONTRIBUTING link (file is at project root, not in docs)
- vision.md, landing.mdx: standardize American English spelling (personalized not personalised)

Build verification: npm run build passes with SUCCESS.

Author: UltimaPhoenix

docs/index.mdx

@@ -31,4 +31,4 @@ Start with the [landing page](/), then return here for detailed guides.
 ## Roadmap & contributing
 
 - **[Vision & roadmap](./vision.md)** — free now, teams and courses planned
-- **[CONTRIBUTING](../CONTRIBUTING.md)** — fork, develop, submit a PR
+- **[CONTRIBUTING](https://github.com/UltimaPhoenix/dev-coach/blob/main/CONTRIBUTING.md)** — fork, develop, submit a PR

docs/vision.md

@@ -38,7 +38,7 @@ For engineering organisations, a hosted version will offer:
 
 - **Per-developer knowledge profiles** — each developer's knowledge map, calibrated to their
   actual stack and experience level
-- **Personalised learning paths** — structured progression tailored to the individual, not a
+- **Personalized learning paths** — structured progression tailored to the individual, not a
   generic curriculum
 - **Team-level visibility** — which topics the team is collectively strong or weak on; where
   coverage is thin; what skills are concentrated in one person

website/src/pages/landing.mdx

@@ -11,8 +11,8 @@ import ThemedShot from "@site/src/components/ThemedShot";
     You're shipping more than ever and understanding less. devcoach fixes that with one lesson at a time, delivered right after your agent completes a task.
   </p>
   <div style={{ display: "flex", gap: "1rem", justifyContent: "center", flexWrap: "wrap" }}>
-    <a href="/install/index.md" style={{ padding: "0.75rem 1.5rem", backgroundColor: "var(--ifm-button-background-color)", color: "white", borderRadius: "0.5rem", textDecoration: "none", fontWeight: 600 }}>Install in 30 seconds</a>
-    <a href="/why.md" style={{ padding: "0.75rem 1.5rem", backgroundColor: "var(--ifm-button-background-color-secondary)", borderRadius: "0.5rem", textDecoration: "none", fontWeight: 600 }}>Why it matters</a>
+    <a href="/docs/install" style={{ padding: "0.75rem 1.5rem", backgroundColor: "var(--ifm-button-background-color)", color: "white", borderRadius: "0.5rem", textDecoration: "none", fontWeight: 600 }}>Install in 30 seconds</a>
+    <a href="/docs/why" style={{ padding: "0.75rem 1.5rem", backgroundColor: "var(--ifm-button-background-color-secondary)", borderRadius: "0.5rem", textDecoration: "none", fontWeight: 600 }}>Why it matters</a>
   </div>
 </div>
 
@@ -52,19 +52,19 @@ Pick what fits your workflow:
     <h4 style={{ marginTop: 0 }}>Homebrew (Recommended for developers)</h4>
     <p>macOS/Linux. Get the CLI too.</p>
     <code>brew tap UltimaPhoenix/tap && brew install devcoach</code>
-    <p style={{ fontSize: "0.9rem", color: "var(--ifm-color-emphasis-700)" }}><a href="/install/homebrew.md">Full instructions</a></p>
+    <p style={{ fontSize: "0.9rem", color: "var(--ifm-color-emphasis-700)" }}><a href="/docs/install/homebrew">Full instructions</a></p>
   </div>
   <div style={{ padding: "1.5rem", border: "1px solid var(--ifm-color-emphasis-300)", borderRadius: "0.5rem" }}>
     <h4 style={{ marginTop: 0 }}>Claude Code plugin (One-click)</h4>
     <p>Bundles everything — MCP server, hooks, coaching.</p>
     <code>/plugin install devcoach@ultimaphoenix</code>
-    <p style={{ fontSize: "0.9rem", color: "var(--ifm-color-emphasis-700)" }}><a href="/install/claude-code-plugin.md">Full instructions</a></p>
+    <p style={{ fontSize: "0.9rem", color: "var(--ifm-color-emphasis-700)" }}><a href="/docs/install/claude-code-plugin">Full instructions</a></p>
   </div>
   <div style={{ padding: "1.5rem", border: "1px solid var(--ifm-color-emphasis-300)", borderRadius: "0.5rem" }}>
     <h4 style={{ marginTop: 0 }}>npx (No install)</h4>
     <p>Works immediately, no permanent footprint.</p>
     <code>npx -y devcoach install</code>
-    <p style={{ fontSize: "0.9rem", color: "var(--ifm-color-emphasis-700)" }}><a href="/install/index.md">All methods</a></p>
+    <p style={{ fontSize: "0.9rem", color: "var(--ifm-color-emphasis-700)" }}><a href="/docs/install">All methods</a></p>
   </div>
 </div>
 
@@ -95,17 +95,17 @@ Pick what fits your workflow:
   <h4>Knowledge map</h4>
   <ThemedShot
     alt="Knowledge map"
-    light={require("@site/../docs/screenshots/knowledge-map-light.png").default}
-    dark={require("@site/../docs/screenshots/knowledge-map-dark.png").default}
+    light={require("../../../docs/screenshots/knowledge-map-light.png").default}
+    dark={require("../../../docs/screenshots/knowledge-map-dark.png").default}
   />
 </div>
 
 <div style={{ marginTop: "2rem", marginBottom: "2rem" }}>
   <h4>Lesson history & detail view</h4>
   <ThemedShot
     alt="Lessons"
-    light={require("@site/../docs/screenshots/lessons-light.png").default}
-    dark={require("@site/../docs/screenshots/lessons-dark.png").default}
+    light={require("../../../docs/screenshots/lessons-light.png").default}
+    dark={require("../../../docs/screenshots/lessons-dark.png").default}
   />
 </div>
 
@@ -119,15 +119,15 @@ Competence is built slowly. You can't cram it on demand. The moment you need it
 
 devcoach's bet is simple: a few minutes of genuine learning, delivered in context and spaced across the work you already do, compounds. It's learning on the job, automated.
 
-**[Read the full story →](./why.md)**
+**[Read the full story →](/docs/why)**
 
 ---
 
 ## Roadmap
 
-Free now. Future plans for team/enterprise features: integrated courses, personalised learning paths for teams, team-level visibility into knowledge gaps.
+Free now. Future plans for team/enterprise features: integrated courses, personalized learning paths for teams, team-level visibility into knowledge gaps.
 
-**[Vision & roadmap →](./vision.md)**
+**[Vision & roadmap →](/docs/vision)**
 
 ---