feat: complete structured CLI output

- unify human, plain, and JSON CLI output modes

- standardize diagnostics, lifecycle events, colors, quiet, and verbose handling

- preserve argument forwarding and improve CLI help and summaries

- document and release version 0.9.5

docs/reference/cli-output.mdx

@@ -0,0 +1,34 @@
+---
+sidebar_label: CLI output
+---
+
+# CLI output (experimental)
+
+The structured output implementation is being developed incrementally.
+Currently these global options apply to diagnostics emitted through the logger:
+
+```sh
+dcr --output plain build
+dcr --output json build
+dcr --color never build
+dcr --quiet build
+dcr --verbose build
+```
+
+`--output` accepts `human` (default), `plain`, or `json`.
+Diagnostics are written to stderr. JSON diagnostics are newline-delimited objects
+with `schema_version: 1`, `event`, and `message` fields. Command statuses use the
+shared output helpers, build reporting emits structured lifecycle events, and
+compiler output is represented as JSON events with its original stream and text.
+The protocol is still experimental: some raw command data and subprocess stdout
+remain unstructured.
+
+`--color` accepts `auto`, `always`, or `never`. Automatic coloring requires a
+terminal and respects `NO_COLOR`. Plain and JSON diagnostics never add colors.
+Quiet mode preserves warnings, errors, and compiler diagnostics; verbose mode
+enables debug and trace logging. Arguments following `--` are passed through
+unchanged.
+
+Remaining work includes migrating the remaining raw command data and subprocess
+stdout, improving progress rendering and contextual errors, and expanding
+integration coverage for stdout/stderr and closed pipes.

docs/reference/dcr-toml.mdx

@@ -111,7 +111,11 @@ Never fails the command — warnings only. Pre-release suffixes (`1.0.0-dev`) ar
 | `qt` | `false` | Enable automatic Qt meta-object handling (MOC, UIC, RCC) |
 
 Settings from raw config (not in typed struct):
-- `pkg_config` — list of pkg-config packages
+- `pkg_config` — list of packages queried for build-wide compiler/linker flags
+
+Dependencies can also declare a system package directly, for example
+`fmt = { pkg-config = "fmt" }`. This records the package in `dcr.lock` and applies
+the flags returned by `pkg-config --cflags` and `pkg-config --libs`.
 - `ldscript` — linker script path
 - `build.steps` / `build.post_steps` — codegen steps
 

docs/reference/dependencies.mdx

@@ -6,7 +6,7 @@ sidebar_label: Dependencies
 
 ## Formats
 
-The `[dependencies]` section supports three formats:
+The `[dependencies]` section supports registry, path, Git, and `pkg-config` dependencies:
 
 ### String (registry)
 
@@ -44,6 +44,23 @@ names (`libs`):
 dcr-math = { path = "../deps/dcr-math", include = ["include"], lib = ["lib"], libs = ["dcr-math"] }
 ```
 
+### Table (`pkg-config`)
+
+Use an installed `.pc` package when the library is provided by the operating system
+or another system package manager. DCR invokes `pkg-config --cflags` and
+`pkg-config --libs`, preserving include, library, linker, and other flags:
+
+```toml
+[dependencies]
+fmt = { pkg-config = "fmt" }
+openssl = { pkg-config = ["openssl", "libcrypto"] }
+```
+
+The `pkg-config` executable must be available in `PATH`. The named `.pc` files must
+be available through pkg-config's standard search paths or via `PKG_CONFIG_PATH`.
+These dependencies are not downloaded or built by DCR; they are recorded in
+`dcr.lock` with a `pkg-config+...` source.
+
 ## Registry
 
 DCR uses a package registry for dependency lookup by name.