Add 12 ADRs documenting frontend architecture decisions

docs/decisions/0004-http-interceptors-pipeline.md

@@ -0,0 +1,29 @@
+# ADR 0004: HTTP Interceptors Pipeline
+
+**Date:** 2026-04-26
+**Status:** Accepted
+
+## Context
+
+Every API call requires the same three cross-cutting concerns:
+
+1. Prepend the API base URL so services don't hard-code it.
+2. Attach the JWT bearer token when one exists.
+3. Unwrap error responses into a consistent shape.
+
+Handling these ad hoc in each service would duplicate logic and couple services to environment details.
+
+## Decision
+
+Three functional interceptors are chained in order in `app.config.ts`:
+
+1. **`apiInterceptor`** — prepends `environment.apiBaseUrl` to every outgoing request URL. Consequence: all services call relative paths (e.g. `/skydive/jumps`), never absolute URLs.
+2. **`tokenInterceptor`** — attaches `Authorization: Token <jwt>` when a token exists in `JwtService`.
+3. **`errorInterceptor`** — unwraps `err.error` from HttpErrorResponse and rethrows, so subscribers receive the API error payload directly.
+
+## Consequences
+
+- **Positive:** Services are environment-agnostic. Swapping the API base URL requires changing only `environment.ts`.
+- **Positive:** Auth header injection is transparent to all services.
+- **Positive:** Error handling is uniform across the application.
+- **Constraint:** Services must always use relative paths starting with `/`. Absolute URLs would get the base URL prepended, breaking them.