Add basic Cursor rules (#19864)

* Add basic cursor rules.

* Only apply Python rules when editing Python source code or project files.

Author: nubtron

.cursor/rules/edit-changelog.mdc

@@ -0,0 +1,17 @@
+---
+description: 
+globs: 
+alwaysApply: true
+---
+
+# Adding a changelog entry
+
+## New Features
+`ddev release changelog new added <INTEGRATION> -m "<MESSAGE>"`
+For example:
+`ddev release changelog new added kafka_consumer -m "Bump OpenSSL in confluent-kafka to 3.4.1 on Windows."`
+
+## Fixes
+`ddev release changelog new fixed <INTEGRATION> -m "<MESSAGE>"`
+For example:
+`ddev release changelog new fixed sqlserver -m "Fix a bug where ``tempdb`` is wrongly excluded from database files metrics due to all instances inherited from ``SqlserverDatabaseMetricsBase`` share the same reference of auto-discovered databases."`

.cursor/rules/format-code.mdc

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+---
+description: 
+globs: **/*.py
+alwaysApply: false
+---
+Format code with `ddev test -fs <INTEGRATION>`. For example, for the pgbouncer integration, run `ddev test -fs pgbouncer`.

.cursor/rules/general.mdc

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+---
+description: 
+globs: **/*.py,**/*.toml
+alwaysApply: false
+---
+* Always run unit/integration tests after modifying code files. Run E2E tests only if requested.
+* Always auto-format code with ddev test -fs.

.cursor/rules/testing.mdc

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+---
+description: 
+globs: **/*.py
+alwaysApply: false
+---
+Run unit and integration tests with `ddev --no-interactive test <INTEGRATION>`. For example, for the pbouncer integration, run `ddev --no-interactive test pgbouncer`.
+Run E2E tests with `ddev ddev --no-interactive env test <INTEGRATION> --dev`. For example, for the pbouncer integration, run `ddev ddev --no-interactive env test pgbouncer --dev`.