docs: update README and CONTRIBUTING for v0.2 features

README:
- Quick Start shows kappa add workflow instead of manual configs
- New features: indexed repos, env operators (+=, ?=), conflict reporting
- Updated subcommand table (add, remove, index, validate-index)
- Repo maintenance section (kappa index)
- Link to STYLEGUIDE.md, test counts, CI info

CONTRIBUTING:
- Updated test counts (30+23+85 instead of 31+23)
- Added test-full.sh to mandatory test suite
- Referenced STYLEGUIDE.md in PR requirements
- Updated good-first/ambitious issues for current state

README.md

@@ -72,16 +72,45 @@ kappa rebuild config.kap   # boot.init = "openrc" — only 5 packages actually r
   simultaneously, eight jobs each. The scheduler uses depth-based priority
   grouping so leaf dependencies unblock as much work as possible first.
 
-- **Package recipe caching.** Declare `remotes = ["https://repo.example.com/"]`
-  in your config. Kappa fetches `.kap` files on demand, caches them, and only
-  re-fetches when the remote version is newer.
+- **Package recipe caching with indexed repos.** Declare named repos with
+  channels and mirrors in your config. Kappa fetches `index.kap` from each
+  repo, caches it, and only re-fetches when the remote changes. Package recipes
+  are resolved from the index — fast, offline-tolerant, and mirror-aware.
+
+```kap
+repos {
+    kappa-os {
+        url      = "https://packages.kappa-os.org/"
+        channels = ["stable"]
+        mirrors  = [
+            "https://cdn.kappa-os.org/",
+            "https://eu.kappa-os.org/",
+        ]
+    }
+}
+```
+
+`remotes = [...]` still works. Repos are tried first, then legacy remotes.
 
 - **Source tarball caching.** Downloaded once, stored at `$KAPPA_ROOT/cache/`
   (default: `/usr/local/kappa/cache/`). Rebuilds don't touch the network
   unless versions change.
 
+- **Env operators.** Three ways to set build environment variables:
+  `=` (hard set), `+=` (append with space), `?=` (soft set — only if not
+  already defined). System-level env propagates to all packages.
+
+```kap
+env {
+    CFLAGS  = "-O2 -march=native"    # overwrite
+    CFLAGS += "-pipe"                # append → "-O2 -march=native -pipe"
+    CFLAGS ?= "-g"                   # soft — only if not set
+}
+```
+
 - **Conflicts.** `systemd` declares `conflicts = ["eudev", "elogind"]`. The
-  resolver catches mutual incompatibility before a build starts.
+  resolver catches mutual incompatibility before a build starts — and now
+  actually reports it, rather than silently ignoring it.
 
 - **Init-agnostic system config.** `groups { wheel { gid = 998 } }` — kappa
   creates the groups. `system { hostname = "mybox" }` — kappa writes
@@ -113,41 +142,53 @@ kappa rebuild config.kap   # boot.init = "openrc" — only 5 packages actually r
 cmake -B build -G Ninja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
 cmake --build build
 
-# Write a config
-cat > system.kap << 'EOF'
-system { hostname = "kappa.local" }
-packages { nginx {} }
-services { nginx { enable = true } }
-boot {
-    kernel = "linux"; init = "s6"; root = "/dev/sda1"; bootloader = "limine"
-}
-users { root { shell = "/bin/zsh" } }
-remotes = ["https://packages.kappa-os.org/stable/"]
-EOF
+# Add packages to your system config
+build/kappa add make
+build/kappa add nginx ">=1.24"
+build/kappa add zlib
 
-# Parse it
-build/kappa parse-config system.kap
+# Rebuild — kappa fetches recipes, resolves deps, builds everything
+build/kappa rebuild $KAPPA_ROOT/system/config.kap
 
-# Rebuild
-build/kappa rebuild system.kap
+# Remove packages
+build/kappa remove zlib
 ```
 
+No config files to write by hand. `kappa add` writes the `packages {}` block
+for you. `kappa rebuild` handles the rest.
+
 ### Subcommands
 
 | Command | What it does |
 |---------|-------------|
-| `parse-package <file>` | Validate a `.kap` package definition |
-| `parse-config <file>` | Validate a system configuration |
-| `validate <file>` | Validate any kappa file |
-| `format <file>` | Pretty-print to canonical style |
-| `doctor <file>` | Check for issues and warnings |
-| `resolve <config>` | Compute a build plan |
+| `add <pkg> [version]` | Add a package to system config |
+| `remove <pkg>` | Remove a package from system config |
+| `build <package>` | Build a single package from its `.kap` definition |
+| `rebuild <config>` | Diff config against installed state, rebuild changed |
+| `resolve <config>` | Compute a build plan (shows order, deps, conflicts) |
+| `doctor <file>` | Check a file for issues and warnings |
 | `fetch <package>` | Download and verify source tarballs |
 | `fetch-package <name>` | Fetch a package recipe from remotes |
-| `build <package>` | Build a single package |
-| `rebuild <config>` | Diff config against installed state, rebuild changed |
+| `format <file>` | Pretty-print to canonical style |
+| `index <dir>` | Build an `index.kap` from `.kap` files in a directory |
 | `list` | Show installed packages |
+| `parse-config <file>` | Validate a system configuration |
+| `parse-package <file>` | Validate a `.kap` package definition |
 | `rollback` | Show available generations |
+| `validate <file>` | Validate any kappa file (package, config, or index) |
+
+### Repo maintenance
+
+```sh
+# Generate an index from a directory of .kap files
+kappa index ./packages/
+# → packages/index.kap
+
+# Host the directory behind any HTTP server. That's your repo.
+```
+
+The index is a tiny text file listing every package and version.
+Clients fetch it once, cache it, and check for updates via HTTP headers.
 
 ### License
 
@@ -156,4 +197,7 @@ BSD 2-Clause. Do whatever you want. Just don't sue us.
 ### Contributing
 
 See [CONTRIBUTING.md](CONTRIBUTING.md). We're opinionated but we merge good
-code.
+code. See [STYLEGUIDE.md](STYLEGUIDE.md) for code conventions.
+
+Tests: 138 integration tests across three suites. CI runs on Arch Linux.
+Everything passes or nothing merges.