Re-vendor the shared files from sneak/prompts at dd4027b (closes #504)

The shared workflow, lint config, prettier settings and policies are the copies at `sneak/prompts` commit `dd4027b`. `.gitignore`, `.editorconfig` and `.dockerignore` are the shared copy followed by this repository's own entries. Linting is the image build's lint phase on golangci-lint v2.14.0, and tests run in their own test phase. Every scripted `docker build` passes `--no-cache`, so the CI fingerprint step and the superseded-run script are gone. The binary is built with `-trimpath -s -w`, and a build that has `.git` but no version fails. The development run keeps its databases outside the checkout.

Deviation: `.dockerignore` also leaves out SQLite databases at any depth.

Model: opus-5-5

go.mod

@@ -22,7 +22,6 @@ require (
 	github.com/stretchr/testify v1.11.1
 	go.uber.org/fx v1.24.0
 	golang.org/x/crypto v0.38.0
-	gopkg.in/yaml.v3 v3.0.1
 	gorm.io/driver/sqlite v1.5.4
 	gorm.io/gorm v1.25.5
 	modernc.org/sqlite v1.28.0
@@ -59,6 +58,7 @@ require (
 	golang.org/x/text v0.25.0 // indirect
 	golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d // indirect
 	google.golang.org/protobuf v1.31.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 	lukechampine.com/uint128 v1.2.0 // indirect
 	modernc.org/cc/v3 v3.40.0 // indirect
 	modernc.org/ccgo/v3 v3.16.13 // indirect