feat: resident guest init (#333)

Get this thing going..







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<!-- greptile_summary -->

<h2><a
href="https://app.greptile.com/api/retrigger?id=63134761"><picture><source
media="(prefers-color-scheme: dark)"
srcset="https://greptile-static-assets.s3.amazonaws.com/badges/RetriggerDark.svg?v=1"><source
media="(prefers-color-scheme: light)"
srcset="https://greptile-static-assets.s3.amazonaws.com/badges/Retrigger.svg?v=1"><img
alt="Retrigger"
src="https://greptile-static-assets.s3.amazonaws.com/badges/Retrigger.svg?v=1"
align="right"></picture></a>Confidence Score: 5/5</h2>

The PR appears safe to merge; all previous findings are resolved and the
latest readiness change introduces no established actionable regression.

<h3>Summary</h3>

- Establishes required guest filesystems, runtime directories, device
permissions, and service processes.
- Reports initialization and service deaths over the lifecycle channel.
- Supports launch, restart, and shutdown commands for a resident guest.
- Separates service and workload identities and configures per-launch
runtime environments.
- Removes the currently inactive nescope screenshot option and makes
capture-chain verification fail explicitly when compositor readback is
unavailable.
- Reworks the guest image around `nesinit` as PID 1 without a
distribution service manager.

<h3>Diagram</h3>

```mermaid
sequenceDiagram
    participant Host
    participant Init as nesinit
    participant FS as Guest filesystems
    participant Services as Service stack
    participant Workload

    Init->>Host: Ready(protocol version)
    Host->>Init: Boot(mount descriptors)
    Init->>FS: Establish and mount shares
    Init->>Services: Spawn services in order
    Services-->>Init: Required sockets ready
    Init->>Host: Initialized(service names)
    Host->>Init: Launch(id, exec, on_exit)
    Init->>Workload: Spawn with isolated UID/runtime
    Init->>Host: Started(id)
    Workload-->>Init: Exit status
    Init->>Host: WorkloadExited(id, status)
    Host->>Init: Launch / Restart / Shutdown
```

<sub>Reviews (4) · Last reviewed commit: ["fix(nesinit): readiness is a
socket
that..."](731d34df9d)</sub>

<!-- /greptile_comment -->

---------

Co-authored-by: DatCaptainHorse <DatCaptainHorse@users.noreply.github.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Cargo.lock

@@ -628,6 +628,12 @@ version = "0.8.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "773648b94d0e5d620f64f280777445740e61fe701025087ec8b57f45c791888b"
 
+[[package]]
+name = "core_detect"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f8f80099a98041a3d1622845c271458a2d73e688351bf3cb999266764b81d48"
+
 [[package]]
 name = "cpufeatures"
 version = "0.2.17"
@@ -1022,11 +1028,17 @@ checksum = "edd0f118536f44f5ccd48bcb8b111bdc3de888b58c74639dfb034a357d0f206d"
 
 [[package]]
 name = "encoding_rs"
-version = "0.8.35"
+version = "0.8.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "75030f3c4f45dafd7586dd6780965a8c7e8e285a5ecb86713e63a79c5b2766f3"
+checksum = "2a7a45518d2863d18aa47f4a0cf9faec2aa4304cc09df5e41299f276b3ad135e"
 dependencies = [
  "cfg-if",
+ "core_detect",
+ "multiversion",
+ "multiversion_no_op",
+ "rustversion",
+ "scopeguard",
+ "simdutf8",
 ]
 
 [[package]]
@@ -1243,28 +1255,6 @@ dependencies = [
  "slab",
 ]
 
-[[package]]
-name = "gbm"
-version = "0.18.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ce852e998d3ca5e4a97014fb31c940dc5ef344ec7d364984525fd11e8a547e6a"
-dependencies = [
- "bitflags 2.13.1",
- "drm",
- "drm-fourcc",
- "gbm-sys",
- "libc",
-]
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c13a5f2acc785d8fb6bf6b7ab6bfb0ef5dad4f4d97e8e70bb8e470722312f76f"
-dependencies = [
- "libc",
-]
-
 [[package]]
 name = "generator"
 version = "0.8.9"
@@ -1349,17 +1339,6 @@ dependencies = [
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 ]
 
-[[package]]
-name = "gl_generator"
-version = "0.14.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1a95dfc23a2b4a9a2f5ab41d194f8bfda3cabec42af4e39f08c339eb2a0c124d"
-dependencies = [
- "khronos_api",
- "log",
- "xml-rs",
-]
-
 [[package]]
 name = "glob"
 version = "0.3.4"
@@ -2156,12 +2135,6 @@ dependencies = [
  "wasm-bindgen",
 ]
 
-[[package]]
-name = "khronos_api"
-version = "3.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2db585e1d738fc771bf08a151420d3ed193d9d895a36df7f6f8a9456b911ddc"
-
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -2371,6 +2344,34 @@ dependencies = [
  "uuid",
 ]
 
+[[package]]
+name = "multiversion"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7edb7f0ff51249dfda9ab96b5823695e15a052dc15074c9dbf3d118afaf2c201"
+dependencies = [
+ "multiversion-macros",
+ "target-features",
+]
+
+[[package]]
+name = "multiversion-macros"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b093064383341eb3271f42e381cb8f10a01459478446953953c75d24bd339fc0"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.119",
+ "target-features",
+]
+
+[[package]]
+name = "multiversion_no_op"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "743fb55ba31b18fb1ecef6bdc9aa2743314978ac084044301a7eee33fb99a20d"
+
 [[package]]
 name = "n0-error"
 version = "1.0.1"
@@ -3102,24 +3103,6 @@ dependencies = [
  "tracing",
 ]
 
-[[package]]
-name = "pixman"
-version = "0.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cea217d496c19ac0a8e502b37078e1f683d16344adee9eb247a5d57c165e1edf"
-dependencies = [
- "drm-fourcc",
- "paste",
- "pixman-sys",
- "thiserror 1.0.69",
-]
-
-[[package]]
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-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1a0483e89e81d7915defe83c51f23f6800594d64f6f4a21253ce87fd8444ada"
-
 [[package]]
 name = "pkcs8"
 version = "0.11.0"
@@ -3905,7 +3888,6 @@ dependencies = [
  "atomic_float",
  "bitflags 2.13.1",
  "calloop",
- "cc",
  "cgmath",
  "cursor-icon",
  "downcast-rs",
@@ -3914,14 +3896,9 @@ dependencies = [
  "drm-fourcc",
  "encoding_rs",
  "errno",
- "gbm",
- "gl_generator",
  "indexmap",
  "input",
  "libc",
- "libloading",
- "pixman",
- "pkg-config",
  "profiling",
  "rand 0.9.5",
  "rustix 1.1.4",
@@ -4103,6 +4080,12 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7b2093cf4c8eb1e67749a6762251bc9cd836b6fc171623bd0a9d324d37af2417"
 
+[[package]]
+name = "target-features"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1bbb9f3c5c463a01705937a24fdabc5047929ac764b2d5b9cf681c1f5041ed5"
+
 [[package]]
 name = "target-lexicon"
 version = "0.13.5"