revert: roll back flatpak packaging experiment (#271 + follow-ups) (#297)

Reverts #271, #292, #293, #294, #295, #296.

The flatpak CI pipeline itself works end-to-end, but the installed bundle
surfaced three separate manifest issues during smoke-test on Wayland+NVIDIA:

1. GDK_BACKEND is not set, so without an X11 display in the sandbox GTK
   aborts with "Failed to initialize GTK".
2. libayatana-appindicator3 is not bundled in the GNOME 47 runtime, so
   libappindicator-sys panics the main thread.
3. The release binary is compiled via \`cargo build --release\` rather than
   \`cargo tauri build\`, so the \`custom-protocol\` feature is off and
   Tauri falls back to devUrl — the window opens but shows
   "Could not connect to localhost".

Rolling back so main stays on 1.43.0. A follow-up on the original PR
tracks the fixes needed before re-attempting.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src-tauri/Cargo.lock

@@ -547,9 +547,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.2.61"
+version = "1.2.60"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d16d90359e986641506914ba71350897565610e87ce0ad9e6f28569db3dd5c6d"
+checksum = "43c5703da9466b66a946814e1adf53ea2c90f10063b86290cc9eb67ce3478a20"
 dependencies = [
  "find-msvc-tools",
  "jobserver",
@@ -952,9 +952,9 @@ checksum = "0c87e182de0887fd5361989c677c4e8f5000cd9491d6d563161a8f3a5519fc7f"
 
 [[package]]
 name = "data-encoding"
-version = "2.11.0"
+version = "2.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a4ae5f15dda3c708c0ade84bfee31ccab44a3da4f88015ed22f63732abe300c8"
+checksum = "d7a1e2f27636f116493b8b860f5546edb47c8d8f8ea73e1d2a20be88e28d1fea"
 
 [[package]]
 name = "deranged"
@@ -2506,9 +2506,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.186"
+version = "0.2.185"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "68ab91017fe16c622486840e4c83c9a37afeff978bd239b5293d61ece587de66"
+checksum = "52ff2c0fe9bc6cb6b14a0592c2ff4fa9ceb83eea9db979b0487cd054946a2b8f"
 
 [[package]]
 name = "libloading"
@@ -3653,7 +3653,7 @@ dependencies = [
 
 [[package]]
 name = "psysonic"
-version = "1.43.2"
+version = "1.43.0"
 dependencies = [
  "biquad",
  "discord-rich-presence",
@@ -4173,9 +4173,9 @@ dependencies = [
 
 [[package]]
 name = "rustls"
-version = "0.23.39"
+version = "0.23.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7c2c118cb077cca2822033836dfb1b975355dfb784b5e8da48f7b6c5db74e60e"
+checksum = "69f9466fb2c14ea04357e91413efb882e2a6d4a406e625449bc0a5d360d53a21"
 dependencies = [
  "once_cell",
  "ring",
@@ -4199,9 +4199,9 @@ dependencies = [
 
 [[package]]
 name = "rustls-pki-types"
-version = "1.14.1"
+version = "1.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "30a7197ae7eb376e574fe940d068c30fe0462554a3ddbe4eca7838e049c937a9"
+checksum = "be040f8b0a225e40375822a563fa9524378b9d63112f53e19ffff34df5d33fdd"
 dependencies = [
  "web-time",
  "zeroize",
@@ -4236,9 +4236,9 @@ checksum = "f87165f0995f63a9fbeea62b64d10b4d9d8e78ec6d7d51fb2125fda7bb36788f"
 
 [[package]]
 name = "rustls-webpki"
-version = "0.103.13"
+version = "0.103.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "61c429a8649f110dddef65e2a5ad240f747e85f7758a6bccc7e5777bd33f756e"
+checksum = "8279bb85272c9f10811ae6a6c547ff594d6a7f3c6c6b02ee9726d1d0dcfcdd06"
 dependencies = [
  "ring",
  "rustls-pki-types",
@@ -5841,7 +5841,7 @@ dependencies = [
  "indexmap 2.14.0",
  "toml_datetime 1.1.1+spec-1.1.0",
  "toml_parser",
- "winnow 1.0.2",
+ "winnow 1.0.1",
 ]
 
 [[package]]
@@ -5850,7 +5850,7 @@ version = "1.1.2+spec-1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2abe9b86193656635d2411dc43050282ca48aa31c2451210f4202550afb7526"
 dependencies = [
- "winnow 1.0.2",
+ "winnow 1.0.1",
 ]
 
 [[package]]
@@ -7113,9 +7113,9 @@ dependencies = [
 
 [[package]]
 name = "winnow"
-version = "1.0.2"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2ee1708bef14716a11bae175f579062d4554d95be2c6829f518df847b7b3fdd0"
+checksum = "09dac053f1cd375980747450bfc7250c264eaae0583872e845c0c7cd578872b5"
 dependencies = [
  "memchr",
 ]